Discovery [1] | |
---|---|
Discovered by | J. Chacornac |
Discovery date | October 28, 1854 |
Designations | |
(33) Polyhymnia | |
Pronunciation | /pɒliˈhɪmniə/ [2] |
Named after | Polyhymnia |
A887 HA; 1938 FE; 1953 AK; 1957 YL; 1963 DG; 1976 YT7 | |
Main belt | |
Orbital characteristics [3] | |
Epoch April 18, 2013 (JD 2456400.5) | |
Aphelion | 573.518 Gm (3.83373 AU) |
Perihelion | 284.409 Gm (1.90116 AU) |
428.964 Gm (2.86745 AU) | |
Eccentricity | 0.33698 |
1,773.541 d (4.86 a) | |
256.476° | |
Inclination | 1.869° |
8.595° | |
338.123° | |
Physical characteristics | |
Dimensions | 54.39±11.84 km (infrared) [4] 53.98±0.91 km [5] 64±6 km (occultation) [6] |
18.60888±0.00029 h [7] | |
S [3] or Sq [8] | |
8.55 [3] | |
33 Polyhymnia is a main belt asteroid that was discovered by French astronomer Jean Chacornac on October 28, 1854 [1] and named after Polyhymnia, the Greek Muse of sacred hymns.
Photometric observations of this asteroid at the Organ Mesa Observatory in Las Cruces, New Mexico during 2008 gave a light curve with a period of 18.609 ± 0.002 hours and a brightness variation of 0.15 ± 0.02 in magnitude. This result is in good agreement with a previous study performed during 1980. [9] These results were re-examined with additional observations in 2011, yielding a refined estimate of 18.608 ± 0.001 hours and a brightness variation of 0.18 ± 0.02 magnitude. [10] In 2020, an analysis of photometric data of Polyhymnia from 2008-2019 determined a more precise rotation period of 18.60888±0.00029 h. Two possible north pole orientations of Polyhymnia were also determined, with both solutions indicating an axial tilt of 151–155° (ecliptic latitudes –61° to –65°) with respect to the ecliptic. [7]
Due to its high eccentricity (0.338), it can approach close enough to Earth (minimum orbit intersection distance 0.91 AU) that it can reach up to apparent magnitude 10 in the sky. [11] The orbit of Polyhymnia puts it in a 22:9 mean-motion resonance with the planet Jupiter. The computed Lyapunov time for this asteroid is 10,000 years, indicating that it occupies a chaotic orbit that will change randomly over time because of gravitational perturbations of the planets. [12] Measurements of the position for this asteroid from 1854 to 1969 were used to determine the gravitational influence of Jupiter upon 33 Polyhymnia. This yields an inverse mass ratio of 1,047.341 ± 0.011 for Jupiter relative to the Sun. [13]
In 2012, a study by Benoît Carry estimated a mass of (6.20±0.74)×1018 kg for Polyhymnia based on its gravitational influence on other Solar System bodies. [5] However, given Polyhymnia's diameter of 54 km (34 mi), this mass implies an extremely high density of 75.28±9.71 g/cm3. Such a high density is unrealistic, so this mass and density estimate of Polyhymnia was considered unreliable by Carry. [5] Several other asteroids with diameters similar to Polyhymnia were also measured to have extremely high densities in Carry's study, and were rejected for being unrealistic. [5] Because of Polyhymnia's small size, its gravitational influence on other bodies is extremely difficult to detect and may lead to highly inaccurate mass and density estimates. [5] For example, the 68 km (42 mi)-diameter asteroid 675 Ludmilla was originally measured to have a density of 73.99±15.05 g/cm3 in Carry's study, [5] but improved orbit calculations in 2019 showed that it had a much lower density of 3.99±1.94 g/cm3. [14]
No other peer-reviewed study has attempted to determine a mass and density for Polyhymnia since Carry's study, [15] though in 2023, researcher Fan Li performed a preliminary analysis of Polyhymnia's close approaches with other asteroids and determined a lower mass of (1.03±0.40)×1018 kg. [16] Depending on the diameter used for Polyhymnia, this mass estimate suggests a density of 7.5±3.6 g/cm3 or 12.4 g/cm3, for an occultation-derived diameter of 64 ± 6 km (39.8 ± 3.7 mi) and infrared-derived diameter of 54 km (34 mi), respectively. [16] [17]
Visible light spectroscopy of Polyhymnia from 1995 and 2002 show that it is an S-type asteroid, meaning it is mainly composed of rocky silicates. [3] In particular, Polyhymnia's spectrum exhibits an absorption band at 0.67 μm wavelengths, which indicates olivine and pyroxene on its surface, similar to Q-type asteroids. [8] : 155, 164–165 Since Polyhymnia shares both characteristics of S- and Q-type asteroids, it is further classified as an Sq-type asteroid according to the SMASS classification. [8] : 155, 164–165 Radio telescopes have studied Polyhymnia by radar in 1985. [18] [19]
In 2023, researchers Evan LaForge, Will Price, and Johann Rafelski speculated the possibility that Polyhymnia could be composed of high-density superheavy elements near atomic number 164, if Polyhymnia's extremely high density were correct and superheavy elements could be sufficiently stable. [20] However, as noted above, Polyhymnia very likely does not have such a high density. [16] [17]
The Jupiter trojans, commonly called trojan asteroids or simply trojans, are a large group of asteroids that share the planet Jupiter's orbit around the Sun. Relative to Jupiter, each trojan librates around one of Jupiter's stable Lagrange points: either L4, existing 60° ahead of the planet in its orbit, or L5, 60° behind. Jupiter trojans are distributed in two elongated, curved regions around these Lagrangian points with an average semi-major axis of about 5.2 AU.
624 Hektor is the largest Jupiter trojan and the namesake of the Hektor family, with a highly elongated shape equivalent in volume to a sphere of approximately 225 to 250 kilometers diameter. It was discovered on 10 February 1907, by astronomer August Kopff at Heidelberg Observatory in southwest Germany, and named after the Trojan prince Hector, from Greek mythology. It has one small 12-kilometer sized satellite, Skamandrios, discovered in 2006.
11 Parthenope is a large, bright main-belt asteroid.
18 Melpomene is a large, bright main-belt asteroid that was discovered by J. R. Hind on 24 June 1852, and named after Melpomenē, the Muse of tragedy in Greek mythology. Its historical symbol was a dagger over a star; it is in the pipeline for Unicode 17.0 as U+1CECB .
25 Phocaea is a stony asteroid from the inner regions of the asteroid belt, approximately 75 kilometers in diameter. It is the parent body of the Phocaea family. Discovered by Jean Chacornac in 1853, it was named after the ancient Greek city of Phocaea.
36 Atalante is a large, dark main-belt asteroid. It was discovered by the German-French astronomer H. Goldschmidt on October 5, 1855, and named by French mathematician Urbain Le Verrier after the Greek mythological heroine Atalanta. It was rendered 'Atalanta' in English sources in the 19th century. This asteroid is classified as C-type (carbonaceous), according to the Tholen classification system.
41 Daphne is a large asteroid from the asteroid belt. It is a dark-surfaced body 174 km in diameter is probably composed of primitive carbonaceous chondrites. The spectra of the asteroid displays evidence of aqueous alteration. It was discovered by H. Goldschmidt on May 22, 1856, and named after Daphne, the nymph in Greek mythology who was turned into a laurel tree. Incorrect orbital calculations initially resulted in 56 Melete being mistaken for a second sighting of Daphne. Daphne was not sighted again until August 31, 1862.
46 Hestia is a large, dark main-belt asteroid. It is also the primary body of the Hestia clump, a group of asteroids with similar orbits.
50 Virginia is a large, very dark main belt asteroid. It was discovered by American astronomer James Ferguson on October 4, 1857, from the United States Naval Observatory in Washington, D.C. German astronomer Robert Luther discovered it independently on October 19 from Düsseldorf, and his discovery was announced first.
53 Kalypso is a large and very dark main belt asteroid that was discovered by German astronomer Robert Luther on April 4, 1858, at Düsseldorf. It is named after Calypso, a sea nymph in Greek mythology, a name it shares with Calypso, a moon of Saturn.
57 Mnemosyne is a large main belt asteroid. It is a stony S-type asteroid in composition. This object was discovered by Robert Luther on 22 September 1859 in Düsseldorf. Its name was chosen by Martin Hoek, the director of the Utrecht Observatory, in reference to Mnemosyne, a Titaness in Greek mythology.
84 Klio is a fairly large and very dark main-belt asteroid. It was discovered by R. Luther on August 25, 1865, and named after Clio, the Muse of history in Greek mythology. The name Clio had previously been suggested by the discoverer of 12 Victoria, and that is the name B. A. Gould, editor of the prestigious Astronomical Journal, adopted for that asteroid, because of the controversy over the name Victoria. An occultation by Klio over a dim star was observed on April 2, 1997.
266 Aline is a fairly large main belt asteroid that was discovered by Johann Palisa on 17 May 1887 in Vienna and is thought to have been named after the daughter of astronomer Edmund Weiss. It is a dark C-type asteroid and is probably composed of primitive carbonaceous material. 266 Aline is orbiting close to a 5:2 mean motion resonance with Jupiter, which is located at 2.824 AU.
289 Nenetta is an A-type asteroid with a diameter of 38 km. It was discovered by Auguste Charlois on 10 March 1890 in Nice, France. The asteroid is orbiting the Sun at a distance of 2.87 AU with an eccentricity (ovalness) of 0.204 and an orbital period of 4.87 yr. The orbital plane is inclined at an angle of 6.7° to the plane of the ecliptic.
617 Patroclus is a large binary Jupiter trojan asteroid. It is a dark D-type asteroid and a slow rotator, due to the 103-hour orbital period of its two components. It is one of five Jupiter trojan asteroids targeted by the Lucy space probe, and is scheduled for a flyby in 2033.
675 Ludmilla is a minor planet orbiting the Sun. It was named after Mikhail Glinka's opera Ruslan and Lyudmila.
1143 Odysseus, provisional designation 1930 BH, is a large Jupiter trojan located in the Greek camp of Jupiter's orbit. It was discovered on 28 January 1930, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany, and later named after Odysseus, the legendary hero from Greek mythology. The dark D-type asteroid has a rotation period of 10.1 hours. With a diameter of approximately 125 kilometers, it is among the 10 largest Jovian trojans.
6090 Aulis, provisional designation: 1989 DJ, is a Jupiter trojan from the Greek camp, approximately 70 kilometers in diameter. It was discovered on 27 February 1989, by Belgian astronomer Henri Debehogne at ESO's La Silla Observatory in northern Chile. The dark Jovian asteroid belongs to the 50 largest Jupiter trojans and has a rotation period of 18.5 hours. It was named for the ancient Greek port Aulis, mentioned in the Iliad.
15094 Polymele is a primitive Jupiter trojan from the Greek camp, approximately 21 kilometers in diameter. It is a target of the Lucy mission with a close flyby planned to occur in September 2027. It was discovered on 17 November 1999, by astronomers with the Catalina Sky Survey at Mount Lemmon Observatory, Arizona, in the United States. The P-type asteroid has a rotation period of 5.9 hours and highly flattened shape. It was named after Polymele from Greek mythology, the wife of Menoetius and the mother of Patroclus. In 2022, it was reported to have a natural satellite approximately 5 kilometers in diameter.
23135 Pheidas (provisional designation 2000 AN146) is a large Jupiter trojan from the Greek camp, approximately 66 kilometers (41 miles) in diameter. It was discovered on 7 January 2000, by astronomers with the Lincoln Near-Earth Asteroid Research at the Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, in the United States. The dark Jovian asteroid belongs to the 50 largest Jupiter trojans and has a rotation period of 8.7 hours. It was named after the Athenian warrior Pheidas from Greek mythology.